setValueAtTime-within-block.html

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This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audioparam-interface/setValueAtTime-within-block.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<title>Test setValueAtTime with start time not on a block boundary</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script>

promise_test(function() {

  const bufferSize = 200;

  const offset = 65;

  const sampleRate = 48000;

  const scheduledValue = -2.0;

  var context = new OfflineAudioContext(1, bufferSize, sampleRate);

  var gain = context.createGain();

  gain.gain.setValueAtTime(scheduledValue, offset/sampleRate);

  gain.connect(context.destination);

  // Apply unit DC signal to gain node.

  var source = context.createBufferSource();

  source.buffer =

    function() {

      var buffer = context.createBuffer(1, 1, context.sampleRate);

      buffer.getChannelData(0)[0] = 1.0;

      return buffer;

    }();

  source.loop = true;

  source.start();

  source.connect(gain);

  return context.startRendering().

    then(function(buffer) {

      assert_equals(buffer.length, bufferSize, "output buffer length");

      var output = buffer.getChannelData(0);

      var i = 0;

      for (; i < offset; ++i) {

        // "Its default value is 1."

        assert_equals(output[i], 1.0, "default gain at sample " + i);

      for (; i < buffer.length; ++i) {

        // "If there are no more events after this SetValue event, then for

        // t≥T0, v(t)=V, where T0 is the startTime parameter and V is the

        // value parameter."

        assert_equals(output[i], scheduledValue,

                      "scheduled value at sample " + i);

});

});

</script>